This application claims the priority of German Application No. 198 53 409.4, filed Nov. 19, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a method for determining the severity and pattern of a vehicle collision, by locating a plurality of crash sensors located at various points in the vehicle, whose output signals are fed to an evaluation unit.
This type of method is widely used today. The output signals from a central acceleration sensor and other crash sensors, preferably located on the seat cross members, are fed to the evaluation unit. Together with the trend of providing ever more safety devices such as airbags, seat belt tensioners, etc. in a vehicle, the need to control these devices to suit this trend is also growing. This means, however, that frequently only individual devices are triggered while the rest remain unchanged. For this purpose, many more crash sensors are being provided at various points in the vehicle in order to track a crash event as accurately and directly as possible.
With the increasing number of crash sensors, however, comes the growing problem of being able to interpret the sensor signals correctly. It is known from U.S. Pat. No. 5,583,771 to store the output signal from an individual acceleration sensor for a specific period of time in terms of its pattern and to determine from the signal pattern a number of items of information such as amplitude, speed, etc. This information is entered as input information into a neural network, which alone decides whether an individual airbag is triggered.
If several crash sensors are used, their output signals cannot be analyzed sufficiently accurately in a similar fashion using a neural net. There is also the dependence of acceleration sensors on direction. For example, if the acceleration sensor is able to detect a front-end crash, a side crash then as a rule cannot be detected or at least cannot be detected with the same accuracy. An individual acceleration sensor of this kind as a rule is located centrally in the vehicle. As a result of the vehicle structure, deceleration takes place at the location of the acceleration sensor only with a delay and with a pattern that is completely different from the pattern found for example at the point of impact of an obstacle. As a rule, this results in significant problems in determining the severity of the vehicle collision with sufficient precision.
The goal of the present invention is to provide a method for determining the severity and pattern of a vehicle collision, which method provides a much better indication of the vehicle collision.
The invention achieves this goal by a method for determining the severity and pattern of a vehicle collision, by locating a plurality of crash sensors at various points in the vehicle, whose output signals are fed to an evaluation unit. The output signals from the crash sensors are based on a system of coordinates that is invariable relative to the vehicle. Information about the movement of the sensor locations relative to the system of coordinates can be obtained from the output signals of the crash sensors.
As a result of the plurality of crash sensors, a total of eight for example, it is not only possible to get an idea of the severity but also of the course (pattern) of the vehicle collision--provided its output signals are related to a system of coordinates integral with the vehicle.
The result is a method which makes it possible at low cost to supply information about the severity and course of a vehicle collision rapidly and reliably and to control occupant protective devices as needed.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.